Arc-resistant switchgear enclosures house medium voltage electrical switchgear components such as potential transformers (PT), fuses, circuit breakers, etc. A typical enclosure has plural compartments, with each compartment housing one or more electrical components. Medium voltage generally is in the 5-38 KV range.
Such medium voltage electrical components can experience arc faults. An arc fault creates an explosion of hot gasses which can endanger nearby personnel and equipment.
In order to protect nearby personnel and equipment, enclosures are metal clad and are designed to contain the explosion and vent the explosive gasses in a controlled manner. Personnel and equipment at the front, sides and rear of an enclosure are protected by the walls of the enclosure. The explosive gasses are typically vented up into a plenum which channels the explosive gasses to a safe area, such as a building exterior.
Arc-resistant switchgear enclosures are rated according to the levels of protection provided. A type 2B enclosure is required to protect persons and property outside of the enclosure from an arc fault explosion occurring inside of the enclosure. In the event of an arc fault explosion occurring inside of a compartment, the explosion vents to other compartments inside the enclosure and outside the enclosure into the plenum. Generally, the entire contents of the enclosure are damaged.
In contrast, a type 2C enclosure not only protects outside of the enclosure, but the other compartments inside of the enclosure as well. In the event of an arc fault explosion occurring in one compartment, the explosive gasses are vented into the plenum, while the remaining compartments and their equipment remain isolated due to the dividing walls between the compartments.
Arc-resistant switchgear enclosures typically have a front side and a rear side. The front side is provided with one or more doors to access the front compartment or compartments. Front compartments are preferred for their ease of access by personnel. While type 2B enclosures may have two front compartments for high voltage equipment, which compartments are vertically stacked on top of each other, prior art type 2C enclosures lack this feature. Instead prior art type 2C enclosures have only one front compartment for high voltage equipment due to the need to isolate the compartments from one another in the event of an arc fault explosion.
It is desired to have two front compartments in a type 2C enclosure, which two front compartments can house or contain high voltage equipment.